Telephone system



' H. P. CLAUSEN AND C. L GOODRUM.

TELEPHONE SYSTEM. APPLICATION FILED JUNE 5. 1919.

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HENRY P. CLAUSEN, OF MOUNT VERNON, AND CHARLES I1. GOODR'UM, OF NEW YORK, N. Y., ASSIGNORS 'lO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

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Specification of Letters Patent. Patggnfigd A 19 1921 Application filed June 5, 1919. Serial No. 302,029. 7

the county of Westchester and State of New York, and at New York, in the county of New York and State of New York, respectively, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to machine switching telephonesystems and more particularly to the switching mechanisms whereby telephone lines in such a system are interconnected.

The object of the invention is the provision of an automatic switch which may be more speedily set than the switches in com-' men use to-day.

In accordance with this object, there is provided a switch, simple in construction,

eliicient in operation and easy to manufacture which may be set through the use of approximately half the number of impulses commonly representing a digit.

A feature of the invention is a multiple brush construction in the switch in combi nation with. a novel arrangement of circuits and apparatus which may be controlled by a sendeiysuch as is shown in the patent to Adams, 51,238,076 granted Aug. 28, 1917.

in the drawings, Figure 1 represents diagrammatically a calling substation and a first selector switch; Fig-2 represents dia grammatically a connector switch and a called line.

In general the operation of these switches is controlled by a sender which transmits approximately half the number of impulses as those commonly representing a digit. Such impulses consist in interruption of the line circuit and are so arranged that the trains of impulses representing odd digits will end with an interruption of longer duration than the ordinary interruptions. Such longer interruption is made use, of in the-organization of the switch to cause a change-over from one brush set to another through the use of a slow acting relay.

The circuit arrangement of the switch in cludes the usual line relay, first and second slow relays. In addition it includes a slow acting relay which is so adjusted that it lay having the functions corresponding will not operate on impulses of a duration equal in length of time to the ordinary'impulses transmitted from the substation, but will operate on an impulse of a duration equal to that which ends the series of impulses representing odd digits. This relay, while slow acting, is not quite as slow to pull up as the ordinary first slow relay is to deenergize whereby its action may be taken 1n an interval of time during which the circuit for the first slow relay is broken but which interval is not long enough to allow the first slow relay to retract its armatures.

two sets of brushes, one set of which has access to and may be set on rows of contacts representing even digits and the other set may be in a like manner set on rows of contacts representing odd digits. The change-over from one set of brushes to the other is eflected by the slow-acting relay above described.

In the connector switch, a slow-acting reto the slow-acting relay of the selector switch, does not directly cause the change-over from one brush set to another, but controls the operation of a separate relay for this purpose. In this connector switch there are four sets of brushes. According to the character of the first digit transmitted to the connector one or another of two groups of sets of brushes is selected and according to the character of the last digit one or another of the sets of brushes in. the selected group is in turn selected.

It is thought that the invention will be more readil understood through the fol-- lowing detailed description.

The subscriberat substation A, in removing his receiver from the hook, will cause the extension of his line in the Well-known manner to a first selector switch, as shown diagrammaticallyin Fig. 1. Thereupon a circuit will'be established from battery,,the left-hand winding of line relay to the first position contact, side-switch arm 3 to and through the apparatus of the subscribers substation, the side'-switch 4: and its first position contact, the right-hand winding of the line relay 2 to ground. Through this circuit relay 2 is energized, and through the I terruption of the line circuit.

2, the winding of first slow relay 5 to bat:

'tery and ground. Relay 5 is energized and attracts its armature.

' We will assume that the number of the line wanted is 235. The subscriber at substation A will thereupon actuate the sending device '6 to send a train of impulses representing the digit 2.v According to the before-mentioned patent to Adams, such train of impulses will consist of a single short in- Such interruption will cause the armature of relay 2 to momentarily engage its back contact. This closes a circuit from ground, the armature and back contact of relay 2, the armature and front contact of relay 5 and the winding of second slow relay 7 to battery and ground. One branch from this circuit extends through the side-switch wiper 8 and its first posit-ion contact, the winding of primary magnet 9 to battery and ground and another branch extends through resistance 27, the lower winding of slow-acting relay 24 to battery and ground. Primary magnet 9 raises the shaft 10 one step and places the brush set 11 in operative relation to the row of terminals 12 and the brush set 13 in operative relation to the row of terminals 14. The second slow relay 7 becomes energized, but at the cessation of this single impulse does not retract its armature for a short interval of time after the primary magnet has become deenergized. Upon this first step of the switch, the oil-normal contacts 15, 16 and 17 are closed. Slow-acting relay 24: is unaffected by this short impulse.

Should the first digit of the called telephone number have been odd instead of even, the last impulse would have been long, whereby relay 24 would have been energized long enough to attract its armatures and select the set of brushes 13 instead of the set 11. This last long impulse, however, would not have been long enough to allow relay 5 to retract its armature.

At the end of the interruption of the line, circuit relay 2 attracts its armature and holds it in this condition until the line circuit is interrupted in some manner. This opens the circuit of second slow relay 7 which, after an interval, retracts its armature and thereby closes a circuit from ground, off-normal contact 15, armature and back contact of relay 7, side-switch arm 18 and its first position contact, winding of escape magnet 19 to battery and ground, Escape magnet 19 becomes energized and drives the side-switch arms into their second position. In this position a circuit is established from ground, side-switch arm 20 and its second position contact, back contact and armature of secondary magnet 21 to battery and ground, secondary magnet 21 being seltinterrupting will automatically energize slow relay 51, left-hand armature and back and denergize until its circuit is permanently broken at some other point such as .the sideswitch arm 20. Upon each energization of the secondary magnet 21 the brushes of the selector switch are stepped in a rotary direction one step. We will assume that the line encountered on the first step is an idle one. In this case as soon as the brush 22 encounters the terminal 23 a circuit is established from ground which is found on the terminal 23 as will be hereinafter explained through the brush 22, the

back contact and lowermost armature of the slow relay 24, the second position contact-switch arm 18, the winding of the to escape magnet 19 to battery and ground. The escape magnet 19 is energized in this circuit and shifts the side-switch arms from position 2 to position 3, whereupon the circuit for the secondary magnet 21 is broken and the brushes come to rest on the first set of terminals. Through the side-switch arms 3 and 4, the substation circuit is extended to the circuit of theconnector switch shown in Fig. 2. I

The ground found on the terminal 23 may be traced from ground, the armature and back contact of line relay 50, right hand armature. and back contact of firstcontact of slow relay 51 to the terminal 23. It is important that as soon as the trunk to the connector switch is seized that this ground he removed, first, for the purpose of marking a trunk as busy and second for the purpose of preventing the relay magnet 25 to the selector switch from being energized. As the side-switch arms 3 and 4: move into their third position and the substation cir-' cuit is extended to th'econnector switch the 195 line relay 50 is energized, and by attracting its armature removes the ground from its terminal 23, at the same time placing the connector switch in condition to be actuated by energizing relay 51 which is the first slow releasing relay of the connector.

It was assumed that the called number would be 235, therefore the next series of impulses transmitted from the substation sender will be one-representing the digit 3, in accordance with. the disclosure in the patent to Adams. Such series of impulses will consist of one short interruption of the line circuit, and one long interruption of the line circuit. Upon the first interruption of the 20 line circuit, line relay 50 retracts its armature and establishes a circuit from ground, the armature and back contact of relay 50 and front contact of relay 51, where the circuit divides extending in one direction through the winding of second slow relay 52 to battery and ground, and in the other ditact of relay "52, the Winding of the escape magnet 61, the armature and contact of marthe. point where the circuit dividesthere is also a branch circuit through a resistance 55, the slow acting relay 56- to battery and ground. The first short impulse 1s long enoughin duration to energize second slow relay 52 and the primary magnet 54 but not long enough to energize the slow relay 56. During-the interval between the first short interruption of the line circuit and the second interruption of the line circuit, the pri-,

mary magnet 54' will retract v ,its armature, but the second relay 52 willremain actuated,

When the line circuit is opened forthe transmission of the last long impulse, primary magnet 54 is again energized and causes the stepping of the shaft 57 to the point where the brushsets are placed before their respective second rows of contacts. This impulseis of such duration that the slow relay. 56 becomes energized but not of such duration that the slow relay 51 becomes denergized The energization of relay '56 establishes a circuit for the energization of relay 58, which extends from ground, the

contact and armature of relay '56, the said.

switch arm 59, the lower'winding of relay 58 to battery and ground. Relay 58 becomes energized and completes a lockin circuit over itself extendin from groun the off-normal contact 60 w ich was closedon the first step of the switch, the front contact and upper armature of relay 58, upper winding thereof to battery and round. At

the cessation of this long impu se, the line relay 50 becomes energized and in turn holds the relay 51 energized, but allows after a short interval the retractiorn of the armatures by the second slow relay 52. When the second slow relay 52 had become energized, a circuit was established from ground, the right-hand armature and conginal relay 62 to battery and ground. The escape magnet 61 is arranged to shift the side-switcharms into their second position upon its deenergization upon thedenergization of second slow relay 52.

The energization ofv relay 58 shifts the talking circuit of the connector from the lower group'of brush sets on the shaft 57 to the upper group of brush sets. The con- .nector switch is now in condition for the transmission of impulses representin the units digit. In accordance with the a vementioned patent to Adams, the impulses representing the units or the digit 5 consist of two short impulses followed by one long 1 impulse. In the manner described the line rel'ay 50 will be deenergized twice for short instances of time and onefor a longer period, upon which retraction of its armature it establishes a circuit for the energization of relays 52 and 56 and secondary magnet 63. Relay 52 becomes energized and remains in this condition throughout the sending of the impulses. Relay 56 is unaffected by the short impulses, but will .become energized 'upon the last long impulse. Secondary magnet 63 is energlzed by each impulse and steps the shaft 57 around in a rotary direction three steps.

he energization of relay 56 establishesa circuit from ground to the contact and armature of relay 56, the side-switch arm 59 and its second position, the contact, the loWer-.

most armature and front contact of relay 58, the right-hand winding of relay 64 to and through'its denergization again breaks the-circuit of the escape magnet .61, which through its deenergization causes the shifting .0 the side-switch arms into their third positions, providing thecalled line is idle. The idle condition of-thisli'ne is shown by the absence of ground on the terminal 66.

i If the called line had been busy, a ground on the terminal 66 would have been connected through the brush 67 the outermost, right-hand armature and frontcontact of the relay 64,.the armature 68 and its front contact of rela 58, the side switch arm 69 and its second position contact the lefthand armatureand contact offre ay 52, the off-normal contact 70, the left-hand windmg of relay '71 to battery and ground, whereupon the rela will have become en- 1 ergized and the SWlt'Cll restored to normal.

third position contact and side-switcharm 53, and windingof relay 52 to battery and ground. Relay 52.by attracting'its armatures causes the energization of .the escape.

magnet 61 which in turn causes a circuit for the transmission of ringing current to the called subscribers substation. This ringing current is transmitted from ground, the source of ringing current 7.2, the winding of.- relay 62', the armature and contact of escape magnet 61, a third position contact and side-switch arm 73, the armature-74 and its I front position contact of relay 58, the middle. right-hand armature and front contact of relay 64, the brush 75, the terminal 76 to through the apparatus of the called substation 235, the terminal 77, the brush 7 8, the inner right-hand armature and front contact of the relay 64:, the innermost armature and front contact of the relay 58, the

broken and the side-switch "arms are passedinto their fourth position. In this position talking batte is supplied to the substation 235 through t e agencybf the called supervisory relay 80 and conversation may proceed.

At the conclusion of the conversatio the calling subscriber by replacing his receiver on the hook will cause thedeenergization of the line relay -50 and the consequent deenergization of the first slow rela 51, where 1 upon a circuit will be establlshed from ground, the armature and back contact of relay 50, the right-hand armature and back contact of rela 51 through the oif-normal contact 70 to t e left-hand winding of the rela 71 to battery and ground. Release relay 1 causes the restoration of the'connector switch to its normal position. At the same time a circuit is established from ground, the back contact and armature of relay 50,

the back contact and right-hand armature of relay 51, the left back contact and armature' of relay 51, the terminal 23, the brush 22, the lowermost armature and'back contact of relay 24,, the third position and contact side-switch arm 26, the winding of the release magnet 25 to battery and ground, whereupon the release magnet 25 will become energized-and cause 'the restoration of the selector switch to its normal position.

*What is claimed is: i a

1. In a telephone system, telephone lines, a sender associated with each of said lines, said sender being arranged to transmit-long and short impulses, means for interconnecting said lines including automatic switches, sald switches including a lurality of brush sets, and a slow-acting re ay for selecting a 1 particular one of said brush-sets, said slowactin lmpu ses transmitted by said senders.

' 2. In a telephone system, telephone lines' each including a sender arranged to transmit long and short impulses, means for interrelay being responsive to the long connecting said lines including automatic switches, said switches including a plurality of brush sets, and a slow-acting relay for selecting a' -p'articular'one bf said brush sets, said slow-acting relay being arranged to be energized by each'one of said impulses transmitted by said sender, but to be actuated only by said long impulses.

3.- In a telephone system, telephone lines eachincluding a sender, said sender being arranged to transmit series of impulses some of which series include impulses of longer duration than others, means for interconnecting said lines including automatic switches, said switches including a plurality of brush sets, and a slow-acting relay for selecting a particular one of said brush sets, said sloweactingrelay being arranged to respond to said impulses of longer duration.

4. In an automatic switch, a line relay, a slow-releasing relay, a slowacting relay, and a plurality of brush sets, said slowre'leasin relay being arranged to release in a given length of time, and said slow-acting relay being arranged to act in a length of time somewhat less than the length of time required for the release of said slow-releasing relay, said slow-acting relay being arranged to select a particular one of said brush'sets. f

5. In a telephone system, telephone lines each including a se'nder, said sender being arranged to transmit series of im ulses, some of wh1ch end with an impulse o longerduration than others, means for interconnectin said lines including automatic switches, s-ald switches including a' plurality of brush sets, a line relay, a slow-releasing relay, and

a slow-acting relay, for selecting a particular one of said brush sets, said lin'e relay being responsive to'said impulses, said slow-releasin relay being unresponsive to said impu ses, and said slow-acting-relay being re sponsive only to said impulses of longer duration. 1

In witness whereof we hereunto subscribe our names this 28th da of May, A. D. 1919.

HENRY CLAUSEN. CHARLES L. GOODRUM. 

